Railroad locomotives may experience wheel slip during rainy or icy weather conditions. For example, wheels of a locomotive may slip on a wet or icy railroad track when the locomotive attempts to start pulling stationary railroad cars. The wheels may also slip, for example, when a locomotive operator applies the brakes to stop a fast moving locomotive on a slippery railroad track. Locomotives typically include a sand dispensing system, which dispenses sand near the wheels of the locomotive. The sand comes between the wheels of the locomotive and the railroad track, increasing friction between the contacting surfaces and providing improved traction.
A locomotive operator may detect wheel slip based on signals from a wheel slip sensor. The operator may then push a button or engage a lever to dispense sand from sand boxes located on the locomotive. The operator may, however, be unaware of the amount of sand remaining in the sand boxes or of the flow-rate at which sand is being dispensed. Moreover, when the sand boxes are empty, do not have a sufficient amount of sand, or when the flow-rate of sand is too low, the operator may find it difficult to control the wheel slip. Because of safety restrictions on many railroads, a manual inspection of the sand boxes or the valves, which control the sand flow-rate, before or during operation of the locomotive, is difficult and inaccurate.
One attempt to address some of the problems described above is disclosed in U.S. Pat. No. 8,397,560 of De Sanzo et al. that issued on Mar. 19, 2013 (“the '560 patent”). In particular, the '560 patent discloses a system for monitoring a sand reservoir including at least one sand level indicator. The sand level indicator of the '560 patent provides a visual display external to the sand reservoir to indicate the quantity of sand within the reservoir. The '560 patent further discloses that the sand level indicator can transmit a signal, which indicates the presence or absence of sand in the sand reservoir, to a remote station. In addition, the '560 patent discloses that the sand level and related data may be used, among other things, to avoid an “out of sand” condition, to detect excess sand usage, or to trigger an alert if the sand level has not decreased over a predefined amount of time.
Although the '560 patent discloses a system for monitoring a sand reservoir, the disclosed system may still be inadequate. For example, the system of the '560 patent does not detect the flow-rate of sand from the sand boxes. Thus, the system of the '560 patent may not allow the operator to adjust the flow-rate at which sand is dispensed to adequately respond to a detected wheel slip condition. Moreover, although the system of the '560 patent may detect an “out of sand” condition, it does not provide the operator with any alternative method of providing sand to the wheels of the locomotive.
The sand monitoring and control system of the present disclosure solves one or more of the problems set forth above and/or other problems in the art.